This is a guide to open madam Xiao-Xiao’s strongbox (safe) in The House of Blossoms Upper Level in Chapter 3 Dirty Secrets in Thief.
Overloading the opium: http://wp.me/p1SfP0-1Ge
All Thief guides: http://wp.me/P1SfP0-1FJ
Getting the Combination for the Safe
To open Madam Xiao-Xiao’s Strongbox (safe) you need two documents: Coyle’s Combination and the List of Constellations both of which can be found on the House of Blossoms Upper Level:
Disarming the Trap
Before you open Madam Xiao-Xiao’s Strongbox (safe) use the wire cutters on the box to the right of Madam Xiao-Xiao’s Strongbox (safe) to disable the trap:

Opening Xiao-Xiao’s Strongbox (Safe)
First check Coyle’s Combination for the Star Sign in the documents section of your inventory:

Then look at the List of Constellations and find the numbers associated with the star sign in Coyle’s Combination:

These numbers are the code for the strongbox (safe).